Level measuring device operating with microwaves

Abstract

The microwave measuring device, which preferably operates with microwave bursts, serves to produce a measured value (X H ) representing the level of the contents of a vessel ( 200 ). It comprises a transceiver unit ( 2 ) for generating a level-dependent intermediate-frequency signal (ZF) by means of a transmit signal (S 2 ) and a receive signal (E 2 ), and a transducer element ( 1 ) which in operation couples waves (S 1 ), particularly pulsed waves, into the vessel under control of the transmit signal (S 2 ) and converts echo waves (E 1 ) reflected from the contents ( 201 ) of the vessel into the receive signal (E 2 ). The intermediate-frequency signal (ZF) is fed to a control unit ( 3 ) of the level measuring device where it is stored in the form of a sampling sequence (AF) in a volatile data memory ( 33 ). In this manner, both amplitude information and phase information is available for the level measurement. The device is thus capable of measuring level with high accuracy, particularly accurately to a millimeter, and very fast.

What is claimed is:  
     
       1. A level measuring device operating with microwave bursts, for producing a level value representative of a level in a vessel, said level measuring device comprising: 
       a transceiver unit for generating a level-dependent intermediate-frequency signal by means of a transmit signal and a receive signal;  
       a transducer element which in operation couples transmitted waves, particularly pulsed waves, into the vessel under control of the transmit signal and which converts echo waves reflected from the contents of the vessel into the receive signal; and  
       a control unit with a volatile data memory for storing, at least temporarily, a finite sampling sequence currently representing the intermediate-frequency signal, wherein:  
       the volatile data memory holds, at least temporarily, a digital envelope which represents a temporal amplitude variation of the intermediate-frequency signal; and  
       the volatile data memory holds, at least temporarily, a data record which corresponds to a phase of a data record of the sampling sequence and represents a result of a numerical division of said data record by an essentially equal-locus data record of the envelope.  
     
     
       2. A level measuring device operating with microwave bursts, for producing a level value representative of a level in a vessel, said level measuring device comprising: 
       a transceiver unit for generating a level-dependent intermediate-frequency signal by means of a transmit signal and a receive signal;  
       a transducer element which in operation couples transmitted waves, particularly pulsed waves, into the vessel under control of the transmit signal and which converts echo waves reflected from the contents of the vessel into the receive signal; and  
       a control unit with a volatile data memory for storing, at least temporarily, a finite sampling sequence currently representing the intermediate-frequency signal, wherein:  
       the volatile data memory holds, at least temporarily, a first quadrature-signal sequence, which represents a numerically performed downconversion of at least a portion of the first signal sequence; and  
       the volatile data memory holds, at least temporarily, a data record which corresponds to a phase of a data record of the sampling sequence and represents a numerical division of a data record of the first quadrature-signal sequence by an essentially equal-locus data record of the second quadrature-signal sequence.  
     
     
       3. A level measuring device operating with microwaves for producing a level value representative of a level in a vessel, said level measuring device comprising: 
       a transceiver unit for generating a level-dependent intermediate-frequency signal by means of a transmit signal and a receive signal;  
       a transducer element coupling pulsed microwaves into the vessel under control of the transmit signal, and converting echo waves reflected from the contents of the vessel into the receive signal; and  
       a control unit with a volatile data memory for storing, at least temporarily, a finite sampling sequence currently representing the intermediate-frequency signal, wherein:  
       the volatile data memory holds, at least temporarily, a digital envelope representing a temporal amplitude variation of the intermediate-frequency signal; and  
       the volatile data memory holds, at least temporarily, a data record which corresponds to a phase of a data record of the sampling sequence and represents a result of a numerical division of said data record by an essentially equal-locus data record of the digital envelope.  
     
     
       4. A level measuring device operating with microwaves for producing a level value representative of a level in a vessel, said level measuring device comprising: 
       a transceiver unit for generating a level-dependent intermediate-frequency signal by means of a transmit signal and a receive signal;  
       a transducer element coupling pulsed microwaves into the vessel under control of the transmit signal, and converting echo waves reflected from the contents of the vessel into the receive signal; and  
       a control unit with a volatile data memory for storing, at least temporarily, a finite sampling sequence currently representing the intermediate-frequency signal, wherein:  
       the volatile data memory holds, at least temporarily, a first signal sequence representing a numerically performed multiplication of the sampling sequence by a digital sine-wave signal sequence;  
       the volatile data memory holds, at least temporarily, a second signal sequence representing a numerically performed multiplication of the sampling sequence by a digital cosine-wave signal sequence;  
       the volatile data memory holds, at least temporarily, a second quadrature-signal sequence, which represents a numerically performed downconversion of at least a portion of the second signal sequence; and  
       the volatile data memory holds, at least temporarily, a data record which corresponds to a phase of a data record of the sampling sequence and represents a numerical division of a data record of the first quadrature-signal sequence by an essentially equal-locus data record of the second quadrature-signal sequence.  
     
     
       5. A level measuring device operating with microwaves for producing a level value representative in a vessel, said level measuring device comprising: 
       a transceiver unit for generating a level-dependent intermediate-frequency signal by means of a transmit signal and a receive signal;  
       a transducer element coupling pulsed microwaves into the vessel under control of the transmit signal, and converting echo waves reflected from the contents of the vessel into the receive signal; and  
       a control unit with a volatile data memory for storing, at least temporarily, a finite sampling sequence currently representing the intermediate-frequency signal, wherein:  
       the volatile data memory holds, at least temporarily, first signal sequence representing a numerically performed multiplication of the sampling sequence by a digital sine-wave signal sequence;  
       the volatile data memory holds, at least temporarily, a first quadrature-signal sequence, which represents a numerically performed downconversion of at least a portion of the first signal sequence; and  
       the volatile data memory holds, at least temporarily, a first average-value sequence, which serves in particular to generate the first quadrature-signal sequence and which represents a variation of a time average of at least a portion of the first signal sequence.